Start with the first female nominee of a major party in the 240-year history of the United States; Democrat Hillary Clinton now leads in a campaign that could smash what she famously dubbed "the highest, hardest glass ceiling." Then there's the emergence of white, college-educated women as arguably the most crucial swing group in the electorate, moving away from the GOP in numbers that if not reversed could imperil the party's future.

And this: Allegations of demeaning language and degrading conduct toward women has been the single most problematic issue for Republican Donald Trump, sparking more debate and commentary during the campaign than, say, tax policy or what to do about health care.

Whatever happens on Election Day, this year has been a gender earthquake. It has been recasting the electoral coalitions of the two major parties as highly educated women swing toward the Democrats and men without a college degree move toward the GOP. It's made clear the sort of sexual misconduct that once might have been laughed off or ignored could be the sort of controversy that jeopardizes political ambitions.

Looking ahead, it has expanded the roster of those who realistically could consider running for the nation's top office.

Consider this: In the foreseeable future, will either party be likely to field a national ticket of two white men?

This unprecedented confluence in a presidential campaign reflects broader changes in American life — including an increasing number of women in leadership roles and a declining tolerance for sexual harassment — that can be seen not only in politics but also in business, academia and journalism.

Indeed, the political world isn't leading the way.

"Actually, the large upheavals have already happened," says Sarah Isgur Flores, a Republican strategist who was deputy campaign manager for Carly Fiorina's presidential bid this year. "They happened in the 1980s when women started to enter the workforce in a serious way and in the 1990s when you see the rise of 'sexual harassment' as a term. What we're coming to grips with now is the normalcy of all that."

"This cultural change has been happened gradually over time," agrees Kelly Dittmar, author of Navigating Gendered Terrain: Stereotypes and Strategy in Political Campaigns, published last year. "But this election accentuates it."

'Playing the man card'

In some ways, the presidential contenders personify the debate over women's roles.

"We see in Trump and Clinton the real contrast, particularly in perceptions of gender and traditional gender roles and expectations," says Dittmar, a political scientist at the Center for American Women and Politics at Rutgers University. "Trump really adheres to traditional ... perceptions of masculinity and playing his 'man card' throughout this race. And Clinton is a symbol of breaking the glass ceiling."

During this campaign, Clinton, 69, has embraced her groundbreaking status in a way she didn't eight years ago, in her first run for the Democratic nomination. On the stump, she discusses her delight in being a grandmother. In TV ads, she emphasizes her lifelong interest in helping children and families. As president, she promises to address issues such as equal pay and parental leave.

For his part, Trump, 70, is the first Republican presidential nominee to hire a woman as his campaign manager; GOP pollster Kellyanne Conway was tapped after a campaign shakeup in August. He relies on his 35-year-old daughter, Ivanka, as a leading surrogate and close adviser.

But the thrice-married Trump also has mocked Fiorina's appearance ("Look at that face!" he said derisively in an interview with Rolling Stone), denied the implication by rival Marco Rubio that Trump had a small penis ("I guarantee you there's no problem," he said at a primary debate) and questioned whether Clinton has the "look" a president should have.

"She doesn't have the look; she doesn't have the stamina," he said at the first presidential debate this fall. "I just don't believe she has a presidential look, and you need a presidential look."

Of course, since the nation's 43 presidents to date all have been men, a woman by definition may not have "a presidential look."

A backlash against the idea of a woman as president has helped fueled Trump's core support among men.

In surveys this year by the nonpartisan Public Religion Research Institute, half of Trump supporters said it benefited society for men and women to embrace traditional gender roles; a majority of Clinton supporters disagreed. More than two-thirds of Trump supporters said "society as a whole has become too soft and feminine;" nearly two-thirds of Clinton supporters rejected that idea.

In an online survey by the research software company Qualtrics, released this week, 39% of Trump voters said men made better leaders, dwarfing the 5% who said women made better leaders. (Among Clinton voters, 16% said men made better leaders; 13% said women did.)

But the tough-guy persona that has drawn some male voters to Trump has driven away some female ones.

White, college-educated women supported Republican Mitt Romney by 6 percentage points in the 2012 election; now they back Clinton by double digits. That has been crucial to Clinton's margin in such battleground states as Colorado, Pennsylvania and Virginia. William Frey, a demographer at the Brookings Institution, says the group could be the "linchpin" of a Clinton victory next week and an important asset for Democrats, if the party can hold their support.

The trend was so striking when he analyzed it, Frey says, that "it knocked my socks off."

The release of a 2005 Access Hollywood video in which Trump could be heard boasting about groping and forcibly kissing women was one factor in their flight. Allegations of that sort of conduct, while not exactly unheard of in the past, is less likely these days to be dismissed on college campuses or in the workplace as not credible or unimportant.

Trump's harsh rhetoric about Muslims, Mexicans and American inclusiveness also has hurt him among women, who increasingly have wide horizons, Frey says. "College-educated women are now in the mainstream in the labor force, in positions of responsibility, and they understand the world is changing."

Can a white man be president?

Some analysts liken Clinton's potential impact in the gender debate to President Obama's impact in the past eight years in the nation's debate over race.

If she wins, her presidency automatically would expand the automatic definition of who has "the presidential look," for one. Among other things, it means millions of American middle-schoolers won't be able to remember a time in their lives when a white man was president.

It could open the door a bit wider for the next generation of female officeholders who might be considering presidential bids, such as South Carolina Gov. Nikki Haley, a Republican, or Democratic Sens. Amy Klobuchar of Minnesota and Kirsten Gillibrand of New York.

But Juliet Williams, a professor of gender studies at UCLA, cautions against what she calls the "mythology" that sexism is a thing of the past, saying the 2016 campaign also has revealed "the changes we haven't seen" in attitudes toward women. Clinton has been the target of relentless vitriol on Twitter. Crowds at Trump rallies regularly chant "Lock her up!" and North Carolina Sen. Richard Burr apologized this week for joking about putting a bull's-eye over a photo of Clinton on the cover of a gun magazine.

"The incredibly disrespectful terms in which opposition to Hillary Clinton have been voices (reflect) a fundamental truth, which is that too many people believe they have the right and are entitled to disrespect women," Williams says, though she said her candidacy was also a "cause for celebration" and a sign of progress.

"This is part of the broader culture: There is progress being made even though there are setbacks."

Madeleine Albright, a groundbreaker of her own as the first woman to serve as secretary of State, says Clinton's candidacy has had an impact.

"It has raised the issues that are going to have to be dealt with, like equal pay for equal work, control over our own lives and bodies, and not all of the conversations are going to be comfortable," Albright, 79, who has been campaigning for Clinton, said in an interview. That's been reinforced by the increasing number of women in the ranks of the House and Senate, in the private sector and at universities.

And Albright notes this: If Clinton is elected, she'll be in the White House when the nation celebrates the 100th anniversary of the 19th Amendment, which gave women the right to vote.